How do fluids exert pressure on a container

On a cold day, when the air temperature is 0°c, you empty your lungs and take a deep breath, filling your lungs with 4.2 l of air. if you hold your breath until the temperature of the air in your lungs reaches 37°c, what is the volume of the air in your lungs at that point, assuming the pressure does not change?

Galileo was the first to notice that the moon has craters, valleys, and mountains. how might this have changed people's perception of the moon at the time?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.